This is a really complex question and everyone has their own theories I think.. But I'd like to read some of those theories. My theory is that is a cycle and somehow everything is determined by something or someone, I'm not sure yet if its a god or just a force but I definitely think that we are not alone... What about you? What is your existence theory? (If you have one).
I think we are a species that thrives in having a meaning to our lives. Many people feel this meaning is predetermined by their religion and that gives them joy, so that is great. I think there is no predetermined greater meaning at the species level other than that we should thrive and pursue happiness. Thus each of us not following a predetermined religious path gets to decide what meaning we want our lives to have an pursue that.
I don't know that there is any greater truth to our existence. Like other life forms, we struggle to survive and reproduce. Fortunately for us humans in the modern era, we can enjoy part of the ride whilst doing so. Beyond that, people have been making conjectures on meaning in the form of religion and philosophy for millennia. Maybe someone will eventually figure it out.
Oh god, I've asked this to my self before and all that I can say is that I'm not sure...I guess that I'm not alone, but in case that I were alone, I don't think that I have such a powerful imagination to mentally create all of this wonderful and awful people that are around the world, and that would be really depressing too!
I question why we exist too but there has to be a reason for it all. We are each put on the Earth to complete something for the greater whole. Some people have different reasons for being here. It does not explain why some peopleseem to glide through life while others suffer.
I don't think this is a question that can be answered by anyone but yourself. We all likely will have different answers as to why we're here and what's our purpose. For me, it's about being a good person, spending time with family and friends, and doing things that give me enjoyment in life. That might be an overly simplistic approach to "why we are here," but its a good enough definition for me.
We are here to answer to the unanswered questions: who are we, where have we come from, where are we going to... Basically, to discover the mysteries of life and death.
We are here to to prove to the Universe [we aren't alone here] that no imperfect creature can self-govern without causing pain to those whom they govern. And whilst doing so we are choosing sides. Either we live by the laws of love [love your neighbor as yourself] and at the end of it get to live in a place where love reigns or choose the other side, reject the love and live apart from it once our sojourn here is done.
I just watched the film "rubber" last night. Had I done so prior to my previous post, my answer would have simply been "no reason."